Women will receive either insulin according to the usual protocol or Glibenclamide at an initial dose of 2.5 mg / once daily in the morning before breakfast. So long as the glycemic targets will not be reached doses are gradually increased stepwise every 4 days until day 21 (20mg/j) . Patients who have not reached the glycemic targets at this highest dose will have a change in treatment for insulin at day 21. Routine monitoring of pregnant women with gestational diabetes, up to a week after delivery Number of clinical sites: 15 Perspective: Use of Glibenclamide as a first line treatment of gestational diabetes requiring drug treatment.